This invention relates to a method and apparatus for measuring cut resistance of flexible materials.
This invention was developed due to the need for a simple and reliable test to measure the cut resistance of fabrics used to make protective clothing. Manufacturers and users of protective gloves and other garments previously had no widely accepted means of evaluating the cut protection of such products. Previous cut tests were relatively crude and often very subjective. In some cases the test conditions did not closely simulate the conditions under which the wearer of the protective clothing would actually be cut.
Features of a cut test that are generally desirable include the following. The sample should be tested under conditions similar to those that would be present when the item is in normal use. For example, if a garment is loosely worn, it would not be desirable to test that garment fabric under conditions where it is highly stretched or under high tension. The sharpness of the cutting blade should be the same for each sample tested, since it is well known that the cut resistance of any material is related to the sharpness of the blade that is cutting it. The test conditions should be able to be varied widely so that the speed and force of the cut used during the test can closely simulate the wide variety of cutting conditions that could be encountered in the actual use of a product. The test should be automated as much as practical so that the results are repeatable and not highly subjective. The test should be capable of testing relatively small samples; for example, a fabric only a few inches square. The test should allow a single sample, even a small sample, to be tested several times for more accurate results. The test equipment should be as small and lightweight as practical. A portable tester that could be easily carried by one person would be very desirable.
It is the primary objective of this invention to provide a means of reliably measuring the cut resistance of materials used in the manufacturing of cut protective garments. The invention has been found useful for measuring the cut resistance of almost any flexible article, including films, woven fabrics, nonwoven fabrics, knitted fabrics, felts and papers.